What is Peppol BIS Billing 3.0: Specifications, Format, Example, Benefits

E-invoicing is being mandated across Europe, driven by legal mandates and the clear benefits of efficiency in VAT Gap reduction and cost savings. Even the e-invoicing mandate in Belgium is driven by European Union requirements and national initiatives to modernize invoicing, reduce fraud, and streamline VAT reporting. 

A key component enabling e-invoicing in Belgium is Peppol BIS Billing 3.0, the standard format Belgium uses for e-invoices in government procurement and soon business-to-business transactions. 

This blog will explain Peppol BIS Billing 3.0, how it functions within the e-invoicing ecosystem, the structure of a Peppol BIS invoice, and its benefits for businesses.

EU Mandates and the Belgian Approach for e-Invoicing

The EU passed a Directive in 2014, requiring public sector bodies across member states to accept e-invoices that comply with a common European standard. This led to the creation of EN 16931, a European Norm defining the semantic data model of the core elements of an electronic invoice.

In simple terms, EN 16931 spells out which information an invoice must contain (like supplier details, VAT amounts, etc.) and how it should be structured for consistency.

Belgium has implemented this using the Peppol BIS Billing 3.0 format, which aligns with EN 16931 and meets the EU standard’s requirements. Since April 2019, all Belgian public authorities can receive e-invoices meeting the European standard, and the use of e-invoicing became mandatory for suppliers in public procurement.

If you do business with government agencies in Belgium, you must send invoices electronically in the specified format. Now, Belgium is extending e-invoicing to the B2B sector: a law passed in February 2024 mandates that as of 1 January 2026, all B2B invoices between Belgian VAT registered businesses must be electronic, primarily via the Peppol network using the Peppol BIS 3.0 format. 

What is Peppol BIS Billing 3.0?

Peppol BIS Billing 3.0 is a European standardized format for electronic invoices and credit notes, designed under the Peppol framework. It defines what information an e-invoice should have and how it should be structured, so different business source systems can automatically process it without human intervention and regardless of the software used.

At its core, Peppol BIS stands for:

• Peppol – Pan-European Public Procurement Online
• BIS – Business Interoperability Specification
• Billing 3.0 – Refers to the version of the e-invoice format being used

Key Highlights of Peppol BIS Billing 3.0:

• It is based on the European standard EN 16931, which ensures that all required invoice data (supplier info, VAT details, totals, etc.) is present.
• Built using UBL 2.1 (Universal Business Language) a globally recognized XML structure for electronic business documents.
• Designed to ensure interoperability between companies, software systems, and countries.

What Makes It Different?

Peppol BIS Billing 3.0 is not just any invoice format—it is what’s known as a CIUS:

• CIUS stands for Core Invoice Usage Specification.
• It’s a tailored version of EN 16931 that applies certain business rules or restrictions for specific use cases or regions.

Think of it like this:

• EN 16931 defines the full range of possible fields and structures an invoice might have.
• CIUS (like Peppol BIS 3.0) selects the most relevant elements from that standard and adds specific rules to streamline real-world implementation.

Why Belgium Uses Peppol BIS 3.0

• Universal Format: Peppol BIS 3.0 is intended for broad, cross-border use—making it ideal for both domestic and international transactions.
• No Local CIUS Needed: Belgium has chosen to adopt Peppol BIS 3.0 as-is, without adding a separate national version. This makes adoption simpler and ensures maximum compatibility with European partners.

In Simple Terms, Peppol BIS 3.0 acts like a structured rulebook for e-invoices, ensuring consistency, automation readiness, and legal compliance. Most modern accounting or invoicing software in Belgium supports this format, so businesses don't need to manage the technicalities. Once set up, invoices flow smoothly between systems with fewer errors and faster processing.

How Peppol BIS 3.0 Works in the E-Invoicing Ecosystem?

Peppol BIS Billing 3.0 is more than just a file format it’s part of a much larger ecosystem that enables seamless, automated exchange of e-invoices between businesses and governments.

At the centre of this system is the Peppol network a standardized, global infrastructure for exchanging electronic documents like invoices. You can think of Peppol as a universal postal system for e-invoices. Once you're connected to it, you can send invoices to, or receive them from, anyone else on the network, regardless of the software or service provider they use.

The 4-Corner Model

Peppol operates using a design called the four-corner model, which includes:

1. Supplier (Corner 1): The business creating the invoice.
2. Supplier’s Access Point (Corner 2): The service provider that submits the invoice into the Peppol network.
3. Buyer’s Access Point (Corner 3): The service provider that receives the invoice on behalf of the buyer.
4. Buyer (Corner 4): The company or government department receiving and processing the invoice.

Here’s how it works in practice:

• The supplier creates an invoice in the Peppol BIS 3.0 format.
• That invoice is handed to their chosen Peppol Access Point—similar to handing a letter to the post office.
• The Access Point looks up the buyer’s details (usually via VAT or enterprise number) and routes the invoice to the buyer’s Access Point.
• The buyer’s Access Point delivers the invoice into their accounting system—just like mail delivered to the recipient’s doorstep.
• All Access Points follow Peppol’s global standards, ensuring documents are routed and processed consistently and securely.

Why Peppol BIS Billing Matters

• No custom integrations needed: Businesses can use their preferred Peppol-certified provider without worrying about system compatibility.
• Fully interoperable: Whether you're using a small invoicing tool or a large ERP, as long as it’s Peppol-enabled, everything works together.
• Smooth B2B and B2G communication: The same infrastructure works for both public sector invoicing (B2G) and business-to-business (B2B) exchanges.

Key Rules and Specifications of Peppol BIS 3.0 (Simplified)

One of the reasons Peppol BIS Billing 3.0 was adopted in Belgium is that it lays down clear rules about what an invoice must include and how to represent that information. This makes invoices machine-readable and unambiguous, which is critical for automation. Here is a break down  of some key rules and specifications of BIS 3.0 in layman language

Structure and Peppol BIS 3.0 Format

Peppol BIS 3.0 invoices are structured to support automation, compliance, and interoperability. While users typically don’t see the technical layout, this standardized format ensures invoices are complete, correctly routed, and easily processed by recipient systems—without manual intervention.

Think of it as a digital form with various sections that mirror a traditional invoice, but with a rigid order and labeling that computers expect. 

Here’s a high-level breakdown of a Peppol BIS Billing format:

Example: How an Invoice Looks in Peppol BIS Billing 3.0

Let’s illustrate with a simple example (in plain language) of what an invoice might contain under this format, to make it more concrete. Imagine ABC Manufacturing NV is a Belgian company (VAT: BE1234567890) that sold goods to XYZ Distribution BVBA (VAT: BE0987654321). ABC is issuing an invoice for an order of office chairs. 

Here’s what key parts of that invoice would include in the Peppol BIS 3.0 structure:

• Invoice ID and Date: Invoice number INV-2025-00045 issued on 2025-05-10. It’s marked as an Invoice (as opposed to a Credit Note or other document type).
• Supplier Details: ABC Manufacturing NV, Address: 123 Industrial Lane, 1000 Brussels, BE. VAT: BE1234567890. (This would be under the “AccountingSupplierParty” section in the data model, including that BE1234567890 as the identifier for ABC).
• Buyer Details: XYZ Distribution BVBA, Address: 789 Market Street, 2000 Antwerp, BE. VAT: BE0987654321. (Under “AccountingCustomerParty” in the data, with BE0987654321 as XYZ’s identifier).
• Line Items: Suppose the order was 10 office chairs at €50 each.

Line 1: Product: Office swivel chair, Quantity: 10 units, Unit price: €50.00, Line net amount: €500.00. VAT: 21% standard rate, so VAT amount on this line: €105.00. (The line would also have a line ID like “1” and could include an item code or part number if ABC uses one for chairs).

• Summary Totals: Subtotal (net) = €500.00. Since all items are taxed at 21%, Tax total = €105.00. Grand total = €605.00. The tax breakdown section would clearly indicate: “€500.00 @ 21% VAT => €105.00 tax”.
• Payment Info: Bank account: BE45 6703 synchronization? Actually let's not include something inconsistent - I'd put just "Bank: BE..., BIC: ..., Payment due by 30 days (2025-06-09)". So:
• References: If this invoice was against ABC’s quote or XYZ’s purchase order, that reference could be included. For example, “Order Ref: PO-2025-77”. (In the XML, there are fields for Order Reference etc., which help buyer match the invoice to their internal PO or contract).

Explanation

All of that information would be packed into the Peppol BIS 3.0 XML structure in the proper slots. The end recipient (XYZ’s finance software, or if it’s the government, their Mercurius-connected system) will parse the file and display or record it appropriately.

For a human, the data could be rendered into a readable format (Mercurius, for instance, can generate a PDF view of the XML if needed, so that people can look at invoices without needing to see raw XML). 

But the key is the data is there in a consistent way. In this example, when ABC sends the invoice through the Peppol network, the system will use XYZ’s VAT (BE0987654321) to route it to XYZ’s access point (or Mercurius if it’s a public entity). XYZ’s system receives the data and could automatically, say, check that €605.00 invoice against a receiving report or simply book the expense and VAT. The process becomes faster and less error-prone than emailing a PDF and having someone re-type those numbers.

Benefits of Peppol BIS 3.0 

Adopting Peppol BIS Billing 3.0 simplifies invoicing, improves efficiency, and ensures compliance. It offers tangible gains for both businesses and public sector entities:

• Efficiency and Cost Savings: Invoices flow directly into financial systems without manual re-entry. Automation reduces labour, processing time, and errors—cutting costs and accelerating payments.
• Compliance and Auditability: Built-in validation and standard fields ensure compliance with Belgian and EU requirements. Digital audit trails and status tracking enhance transparency and ease dispute resolution.
• Interoperability: One standardized format enables all systems to exchange invoices seamlessly. Businesses only need to implement e-invoicing once to connect with any Peppol-compliant partner across Europe.
• VAT Fraud Reduction: Real-time and structured data improves transaction visibility for tax authorities. This supports better VAT collection and may eventually reduce other reporting burdens.
• Faster Payments: Instant delivery through the Peppol network shortens invoicing cycles. With automated receipt and approval workflows, suppliers get paid sooner, improving cash flow.
• Fewer Errors and Disputes: Standardized formats and validations catch mistakes early. Invoices align better with purchase orders and receipts, reducing mismatches and manual corrections.
• Process Integration and Data Insights: Digital invoices integrate easily with procurement, inventory, and accounting systems. This allows for automated workflows and improved reporting and analytics.